Document and concept don't have to be seperated as using different ontologies on the same url does seperate them.

example: You won't use foaf on a website URL, it only makes sense on people. So the website document is both "HTML document" and "Person". I think this can work.
The problem is with User Interfaces: Which information shall a user interface filter and show ?
-- LeoSu

Just because you can separate out the ambiguity with some predicates doesn't mean
you can with all, or that it's a good idea. But thanks for angling it this
way so I could see clear to write about OverloadedUri's. -- SandroHawke